Orientation of the Oxygen-Evolving Manganese Complex in a Photosystem II Membrane Preparation: An X-ray Absorption Spectroscopy Study

Mukerji, Ishita; Andrews, Joy C.; DeRose, Victoria J.; Latimer, Matthew J.; Yachandra, Vittal K.; Sauer, Kenneth; Klein, Melvin P.

doi:10.1021/bi00198a042

Cited by 73 publications

(151 citation statements)

References 44 publications

Supporting

Mentioning

135

Contrasting

Order By: Relevance

“…The dichroic ratio (here, amplitude at 90° divided by that at 0°) was taken at the ~ 3260 G. This dichroic ratio ("Signal II ratio") was related to the dichroism in the cytochrome b 559 EPR signal 21,22,112,124,125,128 to obtain the mosaic spread, or half-width of the Gaussian distribution of a particular vector in PS II samples. 126 In previous work from this laboratory, 126 a calibration line has been constructed, which equates mosaic spread to a measured Signal II ratio.…”

Section: Mosaic Spread Determination By Eprmentioning

confidence: 99%

“…To analyze the x-ray absorption linear dichroism of the Sr EXAFS and find the relative orientation of the vector of interest (φ), we used the formalism of Dau et al 121,122 Although it differs somewhat from the previous studies, 21,22,24,101,102 this approach is nevertheless valid and both methods produce comparable results. To a first approximation, the angle dependence of the EXAFS is proportional to cos 2 (θ ER ), with θ ER being the angle between the x-ray electric field vector (E) and the absorber-scatterer vector (R, see Figure 3.1).…”

Section: Theory Of Polarized Exafsmentioning

confidence: 99%

“…Both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) experiments have focused on the Mn atoms of the OEC to obtain oxidation states, 19,20 and structural information about this active site. [21][22][23][24][25][26] Along with manganese and chloride, Ca is an essential cofactor in oxygen evolution. 3,9,27,28 Depleting this cofactor suppresses OEC activity, which can be restored (up to 90%) by replenishing with Ca 2+ .…”

Section: Introductionmentioning

confidence: 99%

“…11,[107][108][109] Without the benefit of suitable crystals for high-resolution x-ray crystallography, 110,111 x-ray absorption spectroscopy (XAS) 7,25,59,61 and electron paramagnetic resonance (EPR) [112][113][114] studies have emerged as the primary methods to provide structural and chemical information about the OEC and devise a working model for its manganese cluster. Because these methods are element-specific and sensitive at dilute concentrations, x-ray absorption near-edge structure (XANES) 19,20,115 and extended x-ray absorption fine structure (EXAFS) [22][23][24][25]46 analyses have been applied at the Mn K-edge to determine oxidation states and information about the local environment of the Mn atoms.…”

Section: Introductionmentioning

confidence: 99%

“…101,121 Specifically, polarized EXAFS has been applied to PS II multilayers that possess an effective membrane normal. 21,22,24,101,102,122 If we collect EXAFS spectra for oriented samples we can extract the relative orientation of the absorber-backscatterer (A-B) vector of interest.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

X-ray absorption spectroscopy on the calcium cofactor to the manganese cluster in photosynthetic oxygen evolution

Cinco¹

1999

View full text Add to dashboard Cite

PS II). To further test and verify whetherCa is close to the Mn cluster, we substituted strontium for Ca and probed from the Sr point of view for any nearby Mn. The extended X-ray absorption fine structure (EXAFS) of Sr-reactivated PS II indicates major differences between the intact and NH 2 OH-treated samples. In intact samples, the Fourier transform of the Sr EXAFS shows a Fourier peak that is missing in inactive samples. This peak II is best simulated by two Mn neighbors at a distance of 3.5 Å, confirming the proximity of Ca (Sr) cofactor to the Mn cluster. In addition, polarized Sr EXAFS on oriented Sr-reactivated samples shows this peak II is dichroic: large magnitude at 10° (angle between the PS II membrane normal and the x-ray electric field vector) and small at 80°. Analysis of the dichroism yields the relative angle between the Sr-Mn vector and membrane normal (23° ± 4°), and the isotropic coordination number for these layered samples.ii X-ray absorption spectroscopy has also been employed to assess the degree of similarity between the manganese cluster in PS II and a family of synthetic manganese complexes containing the distorted cubane [Mn 4 O 3 X] core (X = benzoate, acetate, methoxide, hydroxide, azide, fluoride, chloride or bromide). In addition, Mn 4 O 3 Cl complexes containing three or six terminal Cl ligands at three of the Mn were included in this study. The EXAFS method detects the small changes in the core structures as X is varied in this series, and serves to exclude these distorted cubanes of C 3v symmetry as a topological model for the Mn catalytic cluster.The sulfur K-edge x-ray absorption near-edge structure (XANES) spectra for the amino acids cysteine, methionine, their corresponding oxidized forms cystine and methionine sulfoxide, and glutathione show distinct differences between the thiol and disulfide forms. Sulfur XANES is also used to detect changes (within 5%) of the thiol-to-disulfide ratio in whole human blood, plasma, and erythrocytes.iii To my parents, and to my brothers Raoul and Dannyi v

show abstract

Section: Mosaic Spread Determination By Eprmentioning

confidence: 99%

Section: Theory Of Polarized Exafsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

X-ray absorption spectroscopy on the calcium cofactor to the manganese cluster in photosynthetic oxygen evolution

Cinco¹

1999

View full text Add to dashboard Cite

show abstract

The Mechanism of Water Oxidation: From Electrolysis via Homogeneous to Biological Catalysis

et al. 2010

View full text Add to dashboard Cite

Striving for new solar fuels, the water oxidation reaction currently is considered to be a bottleneck, hampering progress in the development of applicable technologies for the conversion of light into storable fuels. This review compares and unifies viewpoints on water oxidation from various fields of catalysis research. The first part deals with the thermodynamic efficiency and mechanisms of electrochemical water splitting by metal oxides on electrode surfaces, explaining the recent concept of the potential‐determining step. Subsequently, novel cobalt oxide‐based catalysts for heterogeneous (electro)catalysis are discussed. These may share structural and functional properties with surface oxides, multinuclear molecular catalysts and the catalytic manganese–calcium complex of photosynthetic water oxidation. Recent developments in homogeneous water‐oxidation catalysis are outlined with a focus on the discovery of mononuclear ruthenium (and non‐ruthenium) complexes that efficiently mediate O2 evolution from water. Water oxidation in photosynthesis is the subject of a concise presentation of structure and function of the natural paragon—the manganese–calcium complex in photosystem II—for which ideas concerning redox‐potential leveling, proton removal, and OO bond formation mechanisms are discussed. The last part highlights common themes and unifying concepts.

show abstract

Linear Dichroism in the XANES of Partially Oriented Samples: Theory and Application to the Photosynthetic Manganese Complex

Liebisch

Dau

2010

ChemPhysChem

View full text Add to dashboard Cite

For molecular systems which are partially ordered with respect to one macroscopic axis, for example, the sample-surface normal, X-ray absorption spectroscopy (XAS) with linearly polarized synchrotron radiation can provide information on structure and orientation of the X-ray absorbing site (polarized or linear-dichroism XAS). Examples for such partially oriented systems are protein-carrying membrane particles deposited in the form of multilayers on surfaces, layered minerals, surface films or imperfect 2D crystals, planar electrodes or catalytic surfaces. For electric dipole transitions, equations are derived describing how partial unidirectional orientation determines the linear dichroism (LD). The approach presented facilitates description of 1) LD in multiple-scattering contributions of the extended X-ray absorption fine-structure (EXAFS) and 2) of LD in the X-ray absorption near-edge structure (LD-XANES). Structural and orientation information becomes accessible by combination with ab initio XANES calculations. The LD-XANES approach is applied to the water-oxidizing Mn complex of photosystem II. The results suggest that the (mu-O)-(mu-O) vectors of the Mn-(mu-O)(2)-Mn units are at an average angle to the membrane normal of 30-45 degrees. The best-fit structure in connection with crystallographic data suggests a specific oxidation-state assignment: Mn(1)(III)Mn(2)(III)Mn(3)(IV)Mn(4)(IV). However, currently this assignment remains uncertain. In future studies, the LD-XANES analysis should play an important role in construction of unequivocal atomic-resolution model of the photosynthetic Mn complex.

show abstract

Orientation of the Oxygen-Evolving Manganese Complex in a Photosystem II Membrane Preparation: An X-ray Absorption Spectroscopy Study

Cited by 73 publications

References 44 publications

X-ray absorption spectroscopy on the calcium cofactor to the manganese cluster in photosynthetic oxygen evolution

X-ray absorption spectroscopy on the calcium cofactor to the manganese cluster in photosynthetic oxygen evolution

The Mechanism of Water Oxidation: From Electrolysis via Homogeneous to Biological Catalysis

Linear Dichroism in the XANES of Partially Oriented Samples: Theory and Application to the Photosynthetic Manganese Complex

Contact Info

Product

Resources

About